Research On Stability Hierarchical Control Of Four-wheel Independent Drive Electric Vehicle

Due to the increasingly serious global energy crisis and the implementation of sustainable development strategy,the development and promotion of electric vehicles have received extensive attention from the automotive industry and even the national level.Four-wheel independent drive electric vehicle occupies an exclusive position in the field of electric vehicle research due to its unique driving mode,flexible body structure arrangement and high-cfficicncy vehicle crontrol capability.In this paper,the driving stability control of four-wheel independent drive electric vehicle was taken as the research object,a top-down stability hierarchical control strategy was built,the control strategy software simulation verification was co,mpleted.and the hardware-in-the-loop experiment verification was completed based on the stability driving test platform of the target experimental vehicle.Firstly,starting from the demand of cdriving stability control,the theoretical model of vehicle dynamics for four-wheel independent drive electric vehicle was established and the basic simulation contorl models were built,including vehicle dynamics model,tire model,motor model and driver mcodel,etc.At the same time,the CarSim-Simulink software co-simulation platform was built with the four-wheel independent drive electric experimental vehicle as a reference.Secondly,the overall scheme of vehicle driving stability control was determined.The stability control of vehicle driving took the stability of vehicle steering as the research objective,a top-down hierarchical control structure was designed,which included yaw moment decision layer,drive torque distribulion layer and driv ing wheel executive layer.Based on the tracking control of the expected yaw rate,a vehicle yaw moment controller based on fuzzy PID compound control and a driving torque distribution controller were built.The additional yaw moment calculated by the yaw noment decision-making layer and the target driving torque output by the driver driving control model were distributed to each wheel according to the torque rule distribution scheme,and the control cftcct om the top-level yaw moment controller was verified.Then,starting from the relationship between tire force and driving stability,taking full advantage of the independent and controllable driving torque and considering various constraints in the steering process,on the basis of insuff-icient allocation of driving torque rules,a driving force allocation scheme with minimum tire adhesion utilization rate as the optimization objective was proposed and a simulation model was built to verify the control effect.Finally,based on the characteristic parameters of the target experimental vehicle,a driving stability experimental platform based on dSPACE hardware-in-the-loop was built.The experimental results were compared with the software simulation results,which verified the effectiveness of the control strategy.